This invention relates to testing of liquid containing plastic containers for content and integrity and more particularly to the automatic testing of plastic vials filled with liquid.
Testing of sealed packages containing various items has been done for many years. Depending on the product and type of package, various systems have been used to be sure the package integrity has not been breached. Testing for leaks of plastic bags of food items such as potato chips has been done by applying a weight to the bag and measuring the resulting thickness. (U.S. Pat. No. 4,649,740 to Franklin) Flexible packages have also been tested for leaks by applying a ram at a fixed pressure to a package on a scale and noting any change in reading over time (U.S. Pat. No. 5,259,237 to Aarts). Raymond in U.S. Pat. No. 4,862,732 applies a force with a strain gauge and measures the rate of change of the applied force to determine a leak.
After a gross go-no-go test to reject obvious out of tolerance specimens that could damage the actual test apparatus, the present invention subjects a plurality of specimens individually and simultaneously to a predetermined force via strain gauge modules, measures the resistance of the force application at two different times and accepts or rejects the entire plurality of specimens based on a comparison of the measured forces and a predetermined set of values.
Accordingly it is an object of the present invention to provide an apparatus and method for testing simultaneously a plurality of individual liquid containing plastic vials for proper volume content and leakage of fluid therefrom.
It is a further object of the present invention to provide an apparatus and method for automatically testing liquid filled plastic vials as they come off a production line, reject defective vials, and deliver accepted vials to a packaging system.
It is a still further object of the present invention to provide an apparatus and method for simultaneously and automatically testing each individual, vial in a group of two or more liquid filled plastic vials as they travel along a production line.
These and other and further objects of the present invention are achieved with an apparatus for testing liquid filled vials coming off a production line for proper amount of filling and sealing of the vial which places a packet of six vials in a first test station and applies a force to each individual vial simultaneously, measures the amount of force applied, classifies the entire packet a reject if the force applied to a selected number of vials falls outside a predetermined range, transfers each packet to another test station and disables the test station if the packet has been classified reject or applies another force to each vial simultaneously, measures the force applied to each vial, at two different times, compares the two force applications and classifies the entire packet a reject if the measured force applied to any one vial is outside a predetermined value.